Sarah Lurie's first career started unexpectedly when she answered a simple newspaper ad for a part-time sales assistant. She was hired on the spot by a boutique brokerage firm on Wall Street. It was the early 1990s &ndash; a busy time for financial markets -- and she quickly realized that a Series Seven certification would be the ticket to a lucrative career. She earned it before she was 21 years old and left college to work at the brokerage firm full-time.

"I totally got caught up in it," she says of the energy and fervor of working on Wall Street. "I was looking at these men making these huge trades for companies like Coca Cola, and I was like, 'I want to do that too. I want to make this money.' "

But after climbing the ranks to a junior stock trading position at Societe General -- and being one of the only women at the firm at the time -- Ms. Lurie found herself virtually chained to the trading desk for more than 14 hours a day. She says a little voice in the back of her mind asked if there was more to life. A particularly hectic day when she could barely take five minutes to use the bathroom was the last straw.

Making a Change

Never let people push you against your gut. Everybody is going to have advice for you and as a small business owner, and they're always going to think they know which way you should do it. But you really know which way it should be done. Believe in yourself and your idea, and don't let anybody tell you that you can't do it, because you'll have so many naysayers.

Think short term before leaping. In the beginning, if you're leasing space for your business, always sign a shorter lease. You're paying more, but your paying for flexibility and the room to grow.

Always present yourself in a professional manner. Have some type of branding to your business so that when people see it, they associate you with that brand, and always act professionally to back up your brand image.

At 27, after nearly eight years in banking, Ms. Lurie packed up her Upper East Side apartment in 1998 -- and relying on the hefty savings she'd built up, moved to Arizona to live with her mother and finish her degree. "It was kind of scary to give up that independence and really not know what exactly was next," she says.

Ms. Lurie enrolled in a master degree program in economics. It was then &ndash; by accident -- that her second career path became clear. She'd started body building as a way to stay in shape and to satisfy the competitive urges she developed on Wall Street in what she calls her "previous life."

She quickly discovered kettlebells, an ancient Russian technique of using iron weights in a swinging motion, were the only way she could tone her now 30-something body with one motion and one tool. But she could only find them in the elite body-building community. That's when the idea hit her: "I thought if these worked so well for me, then they would work for others," says Ms. Lurie. "And I told myself, 'If you don't do this, someone else is going to do it. Do you want it to be someone else or do you want it to be you?' "

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So she abandoned her economics career &ndash; though not before earning her masters in 2004 &ndash; and used $50,000 in savings and a small-business credit card to launch Iron Core Kettlebells gym in San Diego. She also created a series of professionally-produced, instructional DVDs. Her husband, whom she married just three months prior to launching the business, was, "a little shocked," says Ms. Lurie. "I went from being at home working on my masters to being gone 60 hours a week starting up a business."

The hard work paid off. Within a few months, she noticed people were driving an hour to the gym to take her 45-minute class and within three years, she had to move to a larger space to accommodate the booming membership. The gym now has 160 members and caters to dozens of walk-ins who come just to take classes. Ms. Lurie employs 10 instructors and has 40 personal training clients.

Her followers, like Mike Lucas, 32, are devout. Mr. Lucas joined a local weight-loss contest in San Diego in 2005 where Ms. Lurie was the official trainer. He had already lost 114 pounds going into the contest (it took him 15 months to lose it), and with Lurie's kettlebell workouts, he dropped his last 50 pounds in six weeks. He was so swayed by the training that he left his construction career to became a full-time trainer and teaches 15-20 classes a week at Ms. Lurie's gym.

"She helped inspire me do things even I didn't think I was capable of at the time," he says.

And even though she abandoned her economics training and left Wall Street behind for good, Ms. Lurie says her first career has been valuable in launching &mdash; and sustaining &mdash; her second act. "I really understood a lot about business and finances and the economy," says Ms. Lurie. "When you get a degree in economics, you think a lot differently than someone with an arts degree. It really helped me understand the dynamics of running a business."

Ms. Lurie says she's earning as much as she did in her investment-banking heyday. Earlier this year, executives at fitness empire GoFit recruited her to represent a new line of kettlebells and educational DVDs now found in mass retail outlets like Dick's Sporting Goods, Target and the Home Shopping Network, which could lead to an even more lucrative payday.

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